BUG (?) + GA5 SE gone after C11 Pro -> C12 Pro update (!)

Thought I was crazy at first since I couldn’t get GA5 SE to load in C12 Pro after updating from C11 Pro. Looked in the VST3 folder on my C-dive. All the normal Steinberg VST3’s were there, except GA5 SE that had vanished like a ghost…

After re-installing GA5 SE (v 5.1.11) Cubase throws an error about a REX dll. Se pict.
Anyhow, all seems to work now, incl Rex files in GA5. Just wanted to report this since I suppose more people than me did not see any installation instructions and you are left to your own to figure out what happened.

Advice to Steinberg: You need INSTRUCTIONS that are clear and understandable for the installation process, first time installation AND for updates. Never seen such a messy installation experience, though the old IK M gave you a run for the money. Please think about this in the future, you can probably off load your support if you provide upfront instructions.